Evaluation of a quantitative immunoturbidimetric assay for rheumatoid factors.

Melamies, L.; Ruutsalo, Helka-Marjatta; Nissilä, H

doi:10.1093/clinchem/32.10.1890

Cited by 10 publications

(2 citation statements)

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“…tests appeared based on the agglutination of latex-containing particles of uniform size instead of sheep red blood cells (18). Large scale automation was made possible with the development of nephelometric (19,20) and turbidimetric (21) techniques. Until then, all methods had been isotype-nonspecific, although they all, due to assay format, mainly detected IgM RF.…”

Section: Laboratory Perspectives Autoantibodies In Diagnostic and Classification Criteria For Rheumatoid Arthritismentioning

confidence: 99%

Autoantibodies in Rheumatoid Arthritis – Laboratory and Clinical Perspectives

2021

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Measurement of two groups of autoantibodies, rheumatoid factor (RF) and anti-citrullinated protein/peptide antibodies (ACPA) have gained increasing significance in the diagnosis and classification of rheumatoid arthritis (RA) over the last 65 years. Despite this rising importance of autoimmune serology in RA, there is a palpable lack of harmonization between different commercial RF and ACPA tests. While a minimal diagnostic specificity has been defined for RF tests, which almost always are related to an international reference preparation, neither of this applies to ACPA. Especially assays with low diagnostic specificity are associated with very low positive predictive values or post-test probabilities in real world settings. In this review we focus on issues of practical bearing for the clinical physician diagnosing patients who potentially have RA, or treating patients diagnosed with RA. We advocate that all clinically used assays for RF and ACPA should be aligned to a common diagnostic specificity of 98-99% compared to healthy controls. This high and rather narrow interval corresponds to the diagnostic specificity seen for many commercial ACPA tests, and represents a specificity that is higher than what is customary for most RF assays. Data on antibody occurrence harmonized in this way should be accompanied by test result-specific likelihood ratios for the target diagnosis RA on an ordinal or interval scale, which will provide the clinical physician with more granular and richer information than merely relating numerical values to a single cut-off point. As many physicians today are used to evaluate autoantibodies as positive or negative on a nominal scale, the introduction of test result-specific likelihood ratios will require a change in clinical mindset. We also discuss the use of autoantibodies to prognosticate future arthritis development in at-risk patients as well as predict severe disease course and outcome of pharmacological treatment.

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Section: Laboratory Perspectives Autoantibodies In Diagnostic and Classification Criteria For Rheumatoid Arthritismentioning

confidence: 99%

Autoantibodies in Rheumatoid Arthritis – Laboratory and Clinical Perspectives

2021

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“…Erythrocyte aggregation depends on both its mechanical properties and on its surface characteristics. It takes place in the presence of macromolecules able to trigger such phenomenon in the medium [4,22,23].…”

Section: Discussionmentioning

confidence: 99%

Erythrocyte aggregation in rheumatoid arthritis: Cell and plasma factor's role

Luquita

Urli

Svetaz

et al. 2009

Clinical Hemorheology and Microcirculation

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Increase in erythrocyte aggregation (EA) is pathognomonic for rheumatoid arthritis (RA), and its estimation through erythrocyte sedimentation rate (ESR) is part of DAS 28-4 activity diagnosis, with low correlation with EA and that does not discriminate the contribution of cell factors that increase aggregation.Objective: To analyse cell and plasma factors that might be involved in EA increase, to understand how RA affects blood components, thus modifying blood fluid behavior.Methodology: One hundred women presenting active RA were compared with age-matched controls (C). EA was measured by transmitted light, obtaining two parameters: 2k 2 n 0 , characterizing the aggregation process kinetics and s 0 /n 0 , estimating aggregates size. Cell factors assays: erythrocyte deformability, by filtration through nucleopore membranes, cell shape, by microscopy, and membrane fluidity by EPR. Plasma: total proteins and CRP, albumin, fibrinogen (Fb), by gravimetry, and IgG and IgM by single radial immuno-diffusion.Results: AR and C (x ± SE). 2k 2 n 0 : 31.83 ± 2.84, 23.75 ± 1.91; s 0 /n 0 : 0.92 ± 0.05, 0.87 ± 0.04. Rigidity index (RI):

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Significance of rheumatoid factors in an eight-year longitudinal study on arthritis

et al. 1988

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A community-based cohort comprising 150 patients with recent-onset seropositive arthritis or seronegative oligoarthritis or polyarthritis was monitored for 8 years. Of the different rheumatoid factor (RF) tests, the initial positivity in the most sensitive assays (latex slide test and IgM-RF by enzyme immunoassay) was the most reliable factor when distinguishing between the erosive and nonerosive cases. The individual RF isotypes fluctuated in four serial specimens, but each patient tended to preserve his or her reactivity pattern. Seroconversion from positive to negative within the 1st year of follow-up did not indicate a particularly good long-term prognosis.

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Evaluation of a quantitative immunoturbidimetric assay for rheumatoid factors.

Cited by 10 publications

References 0 publications

Autoantibodies in Rheumatoid Arthritis – Laboratory and Clinical Perspectives

Autoantibodies in Rheumatoid Arthritis – Laboratory and Clinical Perspectives

Erythrocyte aggregation in rheumatoid arthritis: Cell and plasma factor's role

Significance of rheumatoid factors in an eight-year longitudinal study on arthritis

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